Discover the Best Battery for Your Solar-Powered System Pt 1

Jessica PirroAugust 20, 2019 2242 0

When it comes to evaluating solar power batteries and all of the different options that are on the solar energy market today, like how long the solar power batteries are going to last, or how much solar power it can provide. You can learn, about all of the criteria that you should use to compare your home solar energy storage options as well as the different types of solar power batteries.

How to Evaluate Solar Batteries

Compare Your Solar-Powered System Storage Options

As you start to consider the different solar energy storage options that you have, you are going to come across a lot of complicated product specifications that the solar companies have. The most important ones that you are going to use during your evaluation are the battery’s capacity & power ratings, depths of discharge (DoD), round-trip efficiency, warranty, and manufacturer.

Capacity & Power

Capacity is the total amount of solar electricity that a solar battery can store, measured in kilowatt-hours (kWh). Most of the home solar power batteries are going to be designed to be “stackable,” which will also mean that you can include multiple solar energy batteries with your solar-plus-storage system to get extra capacity.

While the capacity is going to tell you how big your solar power batter is, it isn’t going to tell you how much solar electricity that a battery can provide at any given moment. To understand the full picture, you will also need to consider the battery’s solar power rating. In the context of solar energy batteries, a power rating is the amount of solar electricity that a battery can deliver at one time. It is measured in kilowatts (kW).

A solar power battery that has a high capacity and low power rating that is going to deliver a low amount of solar electricity (just enough to run a few crucial appliances), for quite some time. A solar energy battery with low capacity and a high power-rating could run your entire home, but only for a few hours.

Depth of Discharge (DoD)

Most of the solar power batteries need to retain some charge at all times due to their chemical composition. If you use 100 percent of a battery’s charge, its useful life is going to be significantly shortened.

The depth of discharge (DoD) of a solar power battery refers to the amount of a battery’s capacity that has been used. Most of the solar companies that manufacturer solar power batteries, are going to specify a maximum DoD for optimal performance. An example, if a 10 kWh solar-powered system battery has DoS of 90 percent, you shouldn’t use more than 9 kWh of the battery before recharging it. A higher DoD means that you will be able to utilize more of your solar power battery’s capacity.

Round- Trip Efficiency of Solar Energy

The round-trip efficiency of solar energy in regards to the solar power batteries is a representation of the amount of solar energy that it took to store it. An example, if you are feeding five kWh of solar electricity back into your solar battery and can only get four kWh of useful solar electricity back, the battery has 80 percent round-trip efficiency of solar energy (4 kWh / 5 kWh = 80%). Generally speaking, a higher round-trip efficiency of solar energy means that you are going to get more economic value out of your solar energy battery.

The Lifetime of a Solar Power Battery & the Warranty

In most uses for solar-powered systems with batteries, the solar power battery is going to “cycle” (charge and drain) daily. The solar energy battery has the ability yo hold a charge is going to, over time, decrease the more you use the battery. In this way, solar power batteries are going to be like the battery in your cell phone. Most people are going to charge their phones at night and use it during the day, and the older your phone gets you will start to know that the battery isn’t going to hold as much of a charge as it did when you first got it.

Your solar power battery is going to have a warranty that will guarantee a certain number of cycles and/or years of useful life. Because all battery performance is going to naturally degrade over time, most solar energy battery manufacturers are going to guarantee that the batter will keep a certain amount of its capacity during the warranty. So the simple answer to “how long will my solar-powered system’s battery last?” is it depends on the brand of the solar energy battery you end up buying means the capacity you are going to lose over time.

A solar power battery may be warrantied for 5,000 cycles or 10 years at 70 percent it is of its original capacity. This is going to mean that at the end of the warranty, the battery will have lost no more than 30 percent of its original ability to store solar energy.


There are alike of different solar companies that are developing and manufacturing solar power battery products, from automotive companies to tech startups. A major automotive company that is entering the solar energy storage market is likely to have a long history of solar product manufacturing, may not be the most revolutionary technology. By contrast, a tech startup might have a brand-new high-performing technology, but less of a track record to prove the battery’s long-term functionality.

Regardless if you choose a battery that is manufactured by a cutting-edge startup or solar company with a long history will depend on your priorities. Evaluating the warranties that are provided by the solar companies for each product can give you additional guidance as you make your decision.

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